Northern Telecom NT5K17, Description

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1-8 NT5K17 Direct Dialing Inward Trunk Card
553-3001-173 UK Trunk cards description
Table 1-3
Summary of NT5K17 DDI Trunk card signalling states
Si gna l Pu bli c Exchan ge St at e Mer id ia n 1 St at e
I dl e Hi gh I mpedanc e Loop (8.5K
ohm s or gr eat er )
Gr ound on A wi r e
- 48V on w i r e
Sei z e Low I mpedanc e Loop
( 2.2 K ohm s or l es s) —
Di al i ng Br eak : Hi gh Im pedance Loop
Mak e: Low I mpedanc e Loop —
Ans wer — - 48V on w i r e
Gr ound on B wi r e
Publ i c Ex change
di s connec ts f i r st
( Far End Rel eas e)
Hi gh I mpedanc e Loop —
Fa r End Rel eas e
ac know l edgement —
Gr ound on A wi r e
- 48V on B wi r e
Mer i di an 1 di sc onnect s
f ir s t
( Near End Rel eas e)
—
Gr ound on A wi r e
- 48V on B wi r e
Ne ar End Rel eas e
ac know l edgement Hi gh I mpedanc e Loop —
Bac kw ar d Bus y — Open Ci r c ui t on A wi r e
Open Ci r c ui t on B wi r e
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